Rainbow Trout Fishing

Rainbow Trout

Other names—steelhead, rainbow, ’bow, redsides, Kamloops, redband trout, Eagle Lake trout, Kern River trout, Shasta trout, San Gorgonio trout, Nelson trout, Whitney trout, silver trout; Danish: regnbueørred; Finnish: kirjolohi; French: truite-arc-en-ciel; German: regenbogenforelle; Italian: trota iridea; Japanese: nijimasu; Russian: forel raduzhnaya; Spanish: trucha arco iris; Swedish: regnbåge; Turkish: alabalik türü.

The rainbow trout is one of the most widely distributed freshwater fish, and the one member of the Salmonidae family of salmon, trout, whitefish, and grayling that presently has global distribution. Endemic to western North America and now found on six continents, it was reclassified from the trout genus Salmo to the Pacific salmon genus Oncorhynchus (it was formerly identified as Salmo gairdneri), and occurs in both freshwater resident and anadromous, or sea-run, races. Seagoing rainbows, known as steelhead or steelhead trout, are briefly noted here but are reviewed in greater detail under a separate entry (see: steelhead). One landlocked variety of rainbow trout from the interior of British Columbia is called the Kamloops trout, a genetically large strain called Gerrard trout exists in British Columbia’s Kootenay Lake and its Lardeau River tributary, and there are many other variations (as well as hatchery created hybrids) of rainbows known.

One of the top freshwater sportfish, the rainbow is tolerant of moderate temperatures, which has allowed it to become available to many anglers around the world; this, plus its beautiful coloration and acrobatic tendencies when hooked, have helped make it a favorite in streams, rivers, and lakes.

The rainbow trout is one of the most heavily cultured species of freshwater fish, both for recrea-tional use and for food production. Although natural populations of rainbows are not commercially fished, the species is pond-reared in North America, Europe, and Asia and sold as frozen whole fish. The flesh ranges from bright red in small lake and stream populations to pink or white in large lake and river populations in which the diet is largely piscivorous, and it has an excellent flavor. Commercial fishing for ocean steelhead, however, which have bright orange red flesh, is of significance, resulting in fresh and frozen market sale.

Identification

A close look at a rainbow trout from a Colorado pond.

Rainbow trout possess the typical elongated and streamlined salmonid form, although body shape and coloration vary widely and reflect habitat, age, sex, and degree of maturity. The body shape may range from slender to thick. The back may shade from blue green to olive. There is a reddish pink band along each side about the midline that may range from faint to radiant. The lower sides are usually silver, fading to pure white beneath.

Small black spots are present over the back above the lateral line, as well as on the upper fins and tail. In some locations, the black spots of adults may extend well below the lateral line and even cover the entire lower side. The rainbow and its closest relatives in the Pacific salmon group (cutthroat, golden, Apache, and Gila trout) are known as the “blackspotted” trout because they are covered with numerous prominent black spots. These spots may cover the entire body or may be more abundant near the tail. The spots characteristically extend onto the dorsal fin, the adipose fin, and the tail. Those on the tail radiate outward in an even, orderly pattern. Spots may be present on any of the lower fins, and there are never any red spots such as occur on freshwater and spawning specimens of brown trout (see: trout, brown) and Atlantic salmon (see: salmon, Atlantic). Rainbow trout are positively identified by the 8 to 12 rays in the **** fin, a mouth that does not extend past the back of the eye, and the lack of teeth at the base of the tongue.

The rainbow trout’s coloration varies greatly with size, habitat, and spawning periods. Stream dwellers and spawners usually show the darkest and most vivid colors and markings. River or stream residents normally display the most intense pink stripe coloration and heaviest spotting, followed by rainbows from lake and lake-stream systems. By contrast, the steelhead is silvery and may not have a pink stripe along the middle of its sides.

The rainbow trout readily hybridizes with other “blackspotted” trout, especially with the cutthroat and golden trout, producing fertile offspring with all manner of confusing color combinations and intermediate characteristics. A short-lived but colorful (orange) hatchery-reared rainbow hybrid, crossed with a mutant albino form of golden trout, is called a Palomino trout, and has been widely stocked in Pennsylvania.

The absence of orange red slash marks on the underside of the jaw, and the lack of teeth near the base of the tongue, are good keys for distinguishing rainbows from inland or nonanadromous cutthroat trout (see: trout, cutthroat).

Size/Age

In general, large rainbows are caught in large bodies of water and small ones in streams and ponds. Stream-caught fish commonly weigh a pound or so, whereas fish from larger rivers and lakes commonly weigh between 2 and 4 pounds. Rainbows that have migrated to a large inland lake (called steelhead), such as one of the Great Lakes, may attain double-digit weights, although most weigh 7 to 10 pounds, and sea-run fish likewise become heavyweights. The largest nonanadromous rainbow trout in North America presently come from Alaska and British Columbia waters. World records are kept for all varieties of rainbow trout as one species, meaning that the anadromous form dominates the record books. Rainbows from 20 pounds to more than 30 pounds have been caught, however, and Lake Pend Oreille in Idaho produced a 37-pounder in 1947. Rainbows can live for 11 years but typically have a 4- to 6-year life span.

Distribution

The rainbow trout is native to the West Coast of North America from southern Alaska to Durango, Mexico, and inland as far as central Alberta in Canada and Idaho and Nevada in the United States. It has been extensively introduced across the lower Canadian provinces, throughout the Great Lakes region and the northeastern U.S. to the Atlantic coast and south through the Appalachians to northern Georgia and Alabama, in the western U.S. easterly to western Texas, and sporadically in the central U.S. south of the Great Lakes. It has been transplanted to New Zealand, Australia, South America, Africa, Japan, southern Asia, Europe, and Hawaii. An Asian species known as the Kamchatka trout is believed to be a form of the rainbow trout. It is native to the Amur River in the eastern part of Russia as well as the Kamchatka Peninsula and the Commander Islands.

Habitat

Although rainbows do well in large lakes with cool, deep waters, they prefer moderately flowing streams with abundant cover and deep pools. In most streams they are found in stretches of swift-flowing water, at the edge of strong currents, and at the head of rapids or strong riffles. They prefer water temperatures of 55° to 64°F but can tolerate water to 70°F.

Life history/Behavior

Most varieties of rainbow trout spawn in the spring in small tributaries of rivers, or in inlets or outlets of lakes, but some strains spawn at other times. Rainbow trout usually return to the streams where they hatched.

During late winter or early spring, when water temperatures are on the rise, maturing adult rainbows usually seek out the shallow gravel riffles in their stream or a suitable clear-water stream that enters their lake. Spawning takes place from late winter or early spring through early summer, depending on the specific location and the severity of the winter. The female uses her tail to prepare a nest (redd) 4 to 12 inches deep and 10 to 15 inches in diameter. From 200 to 8,000 eggs are deposited in the redd, fertilized by a male, and covered with gravel.

Hatching normally occurs from a few weeks to as much as four months after spawning, depending on the water temperature. The tiny fry emerge from the gravel in a week or up to several weeks, again depending on the temperature. On emerging, the small trout assemble in groups and seek shelter along the stream margins or protected lakeshore, feeding on crustaceans, plant material, and aquatic insects and their larvae. Rainbow trout rear in similar habitat for the first two or three years then move into the larger water of lakes and streams and turn more to a diet of fish, salmon carcasses, eggs, and even small mammals.

Age of onset of sexual maturity varies markedly among individuals due primarily to such factors as population density, productivity of the aquatic environment, and genetic makeup. In the wild, male and female spawners as young as ages 3 and 5, respectively, have been found, but a majority of both sexes matures at ages 6 to 7. Spawning frequency ranges from annually to once every three years. Fish that live in large productive lakes generally grow largest and live longer than those of river, stream, or pond environs. In Alaska, rainbow trout that live in or migrate to large lakes with sockeye salmon runs generally grow faster and larger than fish that remain year-round in streams.

Food

Rainbows feed on a variety of food, mainly insects, crustaceans, snails, leeches, and other fish if available. Some studies have shown that they feed less often on the surface than brown trout.

Angling

The beauty, strength, endurance, and spectacular leaps of the rainbow trout and all of its variations and strains have endeared it to anglers. It takes lures, flies, and baits well, leaps often, and fights hard no matter what its size, although larger individuals are especially exciting. In rivers that also contain salmon runs, rainbow fishing success is typically greatest in the spring and fall before and after the large salmon runs. Angling methods differ depending on whether the fish are found in rivers or lakes, and are similar to fishing for other trout species. Weighted spinners, wobbling spoons, streamer flies, Muddlers Minnows, and egg- imitation flies fished near the bottom are especially preferred in river and stream habitats.

See: Trout.